US2321392A - Telegraph station break-in system - Google Patents

Description

J 8, 1943,. A. KALIFMAN 2,321,392

TELEGRAPH STATION BREAK-IN SYSTEM Filed Sept. 20, 1941 5 Sheets-Sheet 1 M-H E Q s E I '3 N N Q |||H|I N SAN FRANCISCO FIG.

uvmvrop A, I4. KAUFMAN /g ziws A rromvt TELEGRAPH STATION BREAK-IN SYSTEM Filed Sept. 20, 1941 5 Sheets-Sheet 2 FIG. 2

INVENmR A. W KAUFMAN ATTORNEY June 8, 1943. A. w. KAUFMAN. 2,321,392

TELEGRAPH STATION BREAK-IN SYSTEM File d Sa at. 20, 1941 5 Sheets-Sheet 3 FIG. 5

INVENTOR A. W KAUFMAN .pv, F g

ATTORNEY June 8, 1943. A. w. KAUFMAN TELEGRAPH STATION BREAK-IN SYSTEM Filed Sept. 20, 1941 5 Sheets-Sheet 4 FIG. 6

FIG. 8

INVENTOR A. I4. KAUFMAN ATTORNEY June 8, 1943. w KAUFMAN 2,321,392

TELEGRAPH STATION BREAK-IN SYSTEM Filed se t. 20, 1941 5 Sheets-Sheet 5 INVE/ VTO/Q A. W KAUFMAN BVE-' i J ATTORNEY Patented June 8, 1943 TELEGRAPH STATION BREAK-IN SYSTEM Arthur William Kaufman, San Francisco, Calif., assignor to American Telephone and Telegraph Company, a corporation of New York Application September 20, 1941, Serial No. 411,682

24 Claims.

This invention relates to telegraph systems and particularly to a system having provision for simultaneous two-way transmission of message material.

An object of the invention is to enable a station on a two-way communication channel intermediate to terminal stations to interrupt transmission of one of the terminal stations in order to permit message transmission from the intermediate station.

Another object of the invention is to enable the intermediate station to restart the interrupted transmitter at the conclusion of transmission from the intermediate station.

The invention features a device to interrupt normal transmission from the terminal station to which the intermediate desires to transmit and to cause the transmission from that terminal station of predetermined control signals, after which normal transmission therefrom is resumed.

Th invention also features a device to cause the other terminal station to respond to the control signals to interrupt its transmitter and to respond to the next transmission of the control signals to restart its transmitter.

In accordance with the preferred embodiment of the invention two telegraph stations, presumably located at widely separated points, each consist of a transmitter and a receiver which preferably includes a printing telegraph recorder, and the two stations are interconnected by two communication lines, each of which connects the transmitter of one station to the receiver of the other station. The two communication lines extend through one or more intermediate stations and each such intermediate station includes as a minimum of equipment a transmitter associated with one of the communication lines for transmission to one of the terminal stations, and a receiver associated with the other communication line for reception from said one terminal station.

The receiver at the terminal station to which the one or more intermediate stations may transmit is arranged to respond to a predetermined line condition, such as the opening of the line at an intermediate station, to interrupt normal message transmission from that terminal station if its transmitter is then operating and to set up a special signal, such as the blank signal combination, which is transmitted as long as the predetermined line condition established by the intermediate station continues. The selectable the other terminal station, and which is preferably the blank pull bar, operates in response to the first blank signal combination to prepare a condition for the interruption of the transmitter associated therewith and responds to the next blank signal to operate the transmitter arresting.

mechanism, whereby transmission from the associated transmitter is interrupted and, upon reclosure of the line at the intermediate station which initiated the transmitter interrupting operation, the line will be idle and the intermediate station may proceed to transmit.

At the conclusion of the transmission from the intermediate station the same operations will be initiated by the opening of the line at that intermediate station to signify that transmission therefrom has been concluded. At the terminal station which is responsive to the intermediate station, normal message transmission will be interrupted and the special signal will be transmitted repetitiously on the other communication line as long as the line containing the transmitter at the intermediate station is open. The receiver at the other terminal station will, in response to the first special signal which is preferably the same blank signal combination, prepare for the restarting of the transmitter associated therewith and in response to the second special signal the transmitter will be restarted. The apparatus which is located at the terminal station that is responsive to the intermediate station is so arranged that in the event that the transmitter thereat is not transmitting message material at the time the intermediate station interrupts its transmitting line in order to gain possession of that line, the transmitter at the terminal station will be set in operation to transmit the special signal to the other terminal station in order to effectthe arrestment of the transmitter at said other terminal station.

For a complete understanding of the invention, reference may be had to the following detailed description to be interpreted in connection with the accompanying drawings wherein:

Figure 1 is a diagrammatic view, partly in schematic perspective, showing the transmitter and receiver at one of the terminal stations with the transmitting and receiving line extending therefrom and also showing schematically the transmitter and receiver of one intermediate station associated with the lines;

Fig. 2 is a diagrammatic view, partly in schematic perspective, showing the transmitting and receiving apparatus at the other terminal station with the communication line extending thereto; and Fig. 2 may be placed at the right of Fig. 1

to show, by the combination of Figs. 1 and 2, a complete communication system as contemplated by the invention;

Figs. 3, 4 and 5 are schematic elevational views showing the transmitter controlling mechanism of Fig. 2 in the unoperated, partially operated and completely operated conditions, respectively;

Figs. 6, 7, 8, 9 and are exploded schematic elevational views of the transmitter controlling apparatus in Fig. 1 in several operative conditions from the normal condition of Fig. 6 through the intermediate operative condition of Figs. 7, 8 and 9 to the fully operative condition of Fig. 10.

Referring now to the drawings, and particularly to Fig. l, the reference numeral l6 indicates generally a receiving printer at a station which may be designated as the west station and which is arranged to receive telegraph signals from the east over communication line H. The reference numeral I8 designates generally a transmitter at the west station which is arranged to transmit telegraph signals over the line IS. The line H, inreaching the receiver It, extends through the receiver 2! at an intermediate station indicated generally by the reference numeral 22, and the line 19 extends through a transmitter 23 at the station 22. 1

Referring now to Fig. 2, the line I? has its origin at a transmitter indicated generally by the reference numeral 24 in a station which may be designated as the east terminal station and the line I9 has its terminus in the receiver designated generally by the reference numeral 28 in the same terminal station.

The impulse distributing portion of the transmitter 24 (Fig. 2) consists of a solid ring 27 and a segmented ring 28 traversed by brushes carried by brush arm 29, and the brushes are arranged to connect continuous ring 21 electrically to the segments of ring 28 in succession. Line I! is connected to continuous ring 21. Distributor brush arm 29 is carried by distributor shaft 3| which is arranged to be driven by motor 32 through friction clutch 33, worm 34, and worm gear 35. Shaft 3| is normally restrained against rotation in the position forthe distributor brushes I to engage the stop segment by stop lever 3'! which is presented by spring 38 in position to block stop cam 39 secured to shaft 3!. Lever 31 carries an armature for the normally deenergized start magnet M, one terminal of which is connected to battery 42 and the other terminal of which may be connected to ground over conductor 33 at either of two points as will presently be described.

The start segment of distributor 26 is electrically dead and the code impulse segments are individually connected by conductors 44 to the marking contacts 46 of a tape sensing mechanism indicated generally by the reference numeral ll. Rocker members 48 which are pivotally mounted on and electrically continuous with shaft 49, are movable into extreme clockwise or counterclockwise position to engage respectively marking contacts 46 or dead spacing contacts 5!. Shaft M) is connected by conductor 52 to grounded battery 53. which is also connected to the stop segment of distributor 24.

Transmitting contact rocker members 48 are controlled by tape. sensing levers 5 8 pivoted on shaft 56 and individually biased in counterclockwise direction to seek signal sensing coopto rotatable shaft 5!. Shaft 6| also has secured thereto tape feeding ratchet 62 which is engaged by a pawl 63 pivotally carried by bell crank G l which is pivoted on shaft 53. Each of the tape sensing levers 5 5, is provided with a depending arm 65 which, together with the depending arm of bell crank 64, is engageable by a bail S'l pivoted at 68 and biased in clockwise direction by spring 69. When bail 5'! is in extreme clockwise position tape sensing levers 54 are in extreme counterclockwise position to sense the perforations in tape 51 and bell crank 64 is in extreme counter-clockwise position preparatory to feeding tape 5?. When bail 67 is moved into extreme counterclockwise position it moves tape sensing levers 54 and bell crank id into their extreme clockwise positions thus retracting the tape sensing levers from cooperation with tape 5'! and rotating shaft 6i by means of pawl 63 and ratchet 62 one step in counterclockwise direction to eifect advancement of the tape to bring the next set of code perforations into alignment with the right-hand ends of the sensing levers.

In order to be rocked into extreme counterclockwise position, bail 81 is provided with a depending arm ll, which is engaged by an adjustable abutment screw i2 carried by one end of pivoted lever 13. The other end of lever 13 engages a cam M which is secured to distributor shaft 3!. When the single apex of' cam I l engages lever 13 the lever is rocked into extreme counterclockwise position as viewed in Fig. 2, thereby rocking bail ii? into extreme counterclockwise position to effect withdrawal of sensing levers 55 from cooperation with tape 5'! and also to effect advancement of the tape. As soon as the apex of cam 14 passes out of range of lever 13 the lever is restored to extreme clockwise position by its biasing spring 76, spring 69 restores bail 6'! to extreme clockwise position, spring H restores bell crank 64 to extreme counterclockwise position to pick up the next tooth on ratchet 62, springs 58 rock those of the sensing levers 54 which encounter perforations in the tape to their extreme counterclockwise position and those sensing levers in turn rock their associated transmitting contact rockers 49 into marking position.

Tape 5'! passes under a liftable tape tension member 18 which controls contacts 19. One of the contacts 19 is connected to ground and the other is connected to conductor 8| which may become connected through manually operable switch 82 to conductor 43. When manually operable switch 82 is closed and there is suiiicient slack tape to permit contacts 19 to be closed, the energizing circuit for start magnet 4! will be completed and the magnet will attract its armature and withdraw stop lever 31 from blocking relation to stop cam 39 whereby shaft 3| will be released for continuous rotation to effect the transmission of code combinations contained in tape 51 until tape tension member 18 opens contacts 19 or switch 82 is opened manually. As much of the tape transmitter mechanism shown in Fig. 2 as is described in the foregoing paragraphs is well known in the prior art and further detailed description of its operation is considered unnecessary.

In accordance with the present inventiongthe tape transmitter shown in Fig. 2' has added thereto a combined bail blocking and contact operating lever 86 which is pivoted at 87 on a bracket 85. The left-hand endof lever 86 is undercut to provide a finger which will rest on the upper edge of bail 67 and limit the counterclockwise movement of lever 86 under the influence of its biasing spring 88, and also to provide ashoulder which will block the bail 61 substantially in its extreme counterclockwise position. Lever 86 is provided with an obliquely upwardly extending finger 89 which is normally engaged by a pivoted latching lever 9| on which is mounted the armature of an electroniagnet 92. One terminal of the winding of electromagnet 92 is connected to battery 93 and the other terminal is connected by conductor 94 to one of a pair of normally open contacts 96 associated with receiver 26. The other of the contacts 96 is connected to ground. Lever 86 is provided with a depending finger 9! which, when lever 86 is in extreme counterclockwise position in blocking relation to bail 61, closes the normally open contacts 98. One of the contacts 98 is connected to ground and the other is connected to conductor 43 of start magnet 4| whereby, upon the closure of contacts 98, an energizing circuit for start magnet 4| is completed even though either the tape tension contacts 79 or the manually operable switch 62, or both, may be open.

The bracket 85 which mounts electromagnet 92 and pivotally supports latching lever 9| and blocking lever 86, also pivotally supports a re taining lever 90 for latching lever 9|. Retaining lever 90 is biased in clockwise direction by tension spring 95 and is provided on its right-hand side near the upper end with a latching projection I which comprises a generally horizontal flat upper surface and an oblique or sloping camming surface which slopes downwardly and inwardly from the right edge of the horizontal surface to the body of the retaining lever 90. When latching lever 9| is in released or extreme counter-clockwise position the right-hand edge of latching projection I00 of retaining lever 90 abuts the free end of the latching lever 9|. Upon the energization of the electromagnet 92 latching lever 9| is rocked to its extreme clockwise position and its free end is lifted above the generally horizontal surface of the latching projection I00 of retaining lever 90. The retaining lever is thus permitted to be moved by its spring 95 in clockwise direction to present latching projection I00 underneath the free end of latching lever 9|. Latching lever 9| is thus retained in its operated position and there is prolonged after the deenergization of electromagnet 92 a condition under which blocking lever 86 could not be relatched by latching lever 9|. The reason for the prolongation of this condition will be set forth when the operation of the apparatus is described.

Retaining lever 90 has pivotally mounted thereon a releasing bell crank I05 which has one arm extending longitudinally of the retaining lever 90 and the free end of that arm has connected thereto one end of a tension spring I 09, the other end of which is connected to a post carried by retaining lever 90 in such position as to distend the spring longitudinally of lever 90. Spring I09 thus causes releasing bell crank I05 to assume a position in which the arm to which spring I09 is connected extends toward the mounting post for the spring and the spring yieldably resists pivotal movement of bell crank I05 about its mounting. A block lug IIO carried by retaining lever 90 abuts the downwardly extending arm of bell crank I05 when the bell crank-is in1its normalposition and prevents movement of bell crank I05 from the normal position in a direction other than counter-clockwise. The free end of the laterally extending arm of releasing bell crank I05 is in the form of an oblique camming surface sloping downwardly from left to right.

Blocking lever 86 is provided with a depending arm I I5 which terminates slightly below the free end of the laterally extending arm of releasing bell crank I05 when blocking lever 86 is in extreme clockwise position. Arm II5 of lever 86 carries a pin I20 which extends outwardly (for-.

wardly as viewed in Figs. 3, 4 and 5) from the arm II5 of lever 86 and it is disposed above the. sloping end of the laterally extending arm of bell crank I05 when lever 86 is in extreme clockwise position. The purpose of pin I20 is to engage the sloping outer end of the laterally extending arm of releasing bell crank I05 as blocking lever 86 moves in counter-clockwise direction upon being released by latching lever 9| and since bell crank I05 cannot rock with respect to retaining lever 90 in clockwise direction from its normal position, the pin I20 shifts bell crank I05 leftwardly by the camming action of the sloping free end of the laterally extending arm,- thus rocking retaining lever 96 in counter-clockwise direction to disengage latching projection I 00 from latching lever 9| thereby permitting the lever BI to be restored to extreme counter-clockwise position by its spring, in which position it is capable of relatching the blocking lever 86.

The portion of latching lever 9| which serves to engage arm 89 of blocking lever 85 and to retain the lever in extreme clockwise position is 'a channel-shaped member I25, the flanges of which are provided with ears by which member I is pivotally mounted on latching lever 9| with its web portion parallel and in spaced relation to the lower surface of latching lever 9| at its free end. A compression spring I39 is disposed between the lower surface of latching lever 9| and the web portion of channel member I25 to the right of the pivotal mounting of the channel member, as viewed in Figs. 3, 4, and 5, to bias the channel member in clockwise direction. At its left-hand end the web portion of the channel member I25 lower surface of latching lever 9| and the channeleshaped member I25. The upwardly extending portion I of channel member I25 has a tang I extending into the space between the lower surface of latching lever SI and the web portion of channel member I25 to engage the lower surface of the lever and serve as a stop forpreventing the channel-shaped member I 25 from rotating in clockwise direction under the influence of its compression spring I30 beyond a posi tion at which the web portion of the channel member I25 is substantially parallel with the lower surface of latching lever 9|. The purpose of the pivoted latching member I25 carried by the latching lever 9| is to provide a yieldable latch-- ing element which the tip of arm 89 of blocking lever 86 can traverse to become relatched without materially changing the position of latching lever 9 I, as will presently be described.

As shown in the lower left-hand corner of Fig. 2, the receiver at the east terminal station is represented symbolically by a selector magnet IOI controlled by polarized line relay I02. The selector magnet Illl controls the permutational setting of code bars I03 toeffect the selection of V selectable elements or pull bars, one of Which-is indicated in Fig. 2 by the reference numeral I04. Upon the permutational setting of code bars I03 in the proper positions to effect the selection of pull bar I04, the pull bar willbe moved upwardly in a manner well known, but which will be described later in connection with Fig. 1, 'to effect the momentary closure of contacts 96.

Upon the closure of contacts 96 electromagnet 92 will be energized momentarily and will attract its armature, thus latching lever 6| clear of the upwardly extending finger 86 of bail blocking lever 86, and lever 9| will be retained in substantially its extreme clockwise position by retaining lever 60 after magnet 02 becomes deenergized, it being understood that contacts 95 are closed only momentarily. Lever 86 will then be rocked in counter-clockwise direction by its spring 88 to an extent which depends upon the instantaneous position of bail 61. There is nothing in the communication system herein disclosed to establish any particular phase relationship between the transmission of signals on the line I! and the reception of signals on the line I9, and, accordingly, contacts 96 may be closed and magnet 62 energized at an instant when cam 14 and distributor brush arm 29 occupy any random angular position relative to the stop position of shaft 3|. Accordingly, bail 61 may be in extreme clockwise position or in extreme counter-clockwise position or at any position in its travel in either direction at the instant that magnet 92 is energized and lever 86 is released. Lever 86 can drop into extreme counter-clockwise position in blocking re lation to bail 67 only when the bail is in substantially its extreme counter-clockwise position.

Fig. 3 shows the relation of the parts when lever 86 is held latched by latching lever 9| and electromagnet 92 is deenergized. In this condition of the apparatus, bail 6? is free to rock into extreme clockwise position under the control of lever '13, but is shown held in extreme counterclockwise position by lever I3 with arms 66 of tape sensing levers 54 held in extreme clockwise position to hold the tape sensing levers withdrawn from cooperation with tape 57. In this condition of the apparatus contacts 98 are open.

Fig. 4 shows an instantaneous condition of the apparatus in which electromagnet 62 has been energized and has lifted latching lever 9| to release blocking lever 86 and the latching lever has become held by retaining lever 90. This occurred at an instant when bail 6'! was in or movin toward its extreme clockwise position, so that lever 86, although it has moved counter-clockwise slightly, has been unable to drop into blocking relation with bail 61 and the left-hand end of the lever is resting on top of the bail. This small amount of movement of lever 86 is insufficient to disturb releasing bell crank I05, and latching lever 9| remains held by retaining lever 90. Depending arm 66 of tape sensing levers 54 are at this time in or moving toward their extreme counter-clockwise positions, and those carried by tape sensing levers which encounter perforations in tape ,5! may move into their full counterclockwise positions. This condition obtains until the code combination then being sensed has been transmitted. As shown in Fig. 4, with the lefthand end of lever 80 resting on the top of bail 1, the lever has not moved far enough in counterclockwise direction to close contacts 68 and, accordingly, the contacts remain open.

Fig. shows the condition of the apparatus at the conclusion of the transmission of the signal combination which was in progress in the con dition of the apparatus indicated in Fig. 4. Bail 61 has been restored by lever 13 to extreme counter-clockwise position to move the tape sensing levers into their spacing positions, and with the bail 6'! moved into the position shown, lever 86 has dropped into its extreme counter-clockwise position to prevent movement ofbail 61 in clockwise position even after cam I4 permits lever I3 to release ball 61, and contacts 98 have been closed. The lever 66 in moving to it extreme counter-clockwise position, cams releasing bell crank I05 leftwardly as viewed in Figs. 3 to 5, by means of pin I20, until the pin moves clear of the end of the laterally extending arm of the bell crank, by which time the retaining lever 90 will have been disengaged from latching lever 9 I. Lever 00 then moves into engagement with the end of the released latching lever 9|, and the bell crank I05 moves rightwardly a proportional distance and presents its laterally extending arm above pin I20.

With the tape sensing levers 54 now held in their spacingpositions by blocked bail 61, spacing conditions'will be impressed upon the code segments of distributor ring 28 by rockers 48 and the blank signal combination or all spacing signal will be impressed upon communication line I1, since distributor shaft 3| continues to rotate due to the fact that contacts 98 are closed and have completed an energizing circuit for start magnet 42 regardless of the open or closed condititon of tape tension contacts I9 and manually operable switch 82. Until such time as lever 86 is restored to unoperated position and becomes relatched by latching lever 9|, the transmission of blank signal combinations will continue. The manner in which lever 66 is restored to unoperated position will now be described.

A lever I06 for resetting blocking lever 66 is pivoted at I01. The foremost end of lever I06 as viewed in Fig. 2, is reduced in size, is cylindrical in contour and is fitted loosely into an aperture in lever 86. The other end of lever I06 is formed a a cam follower to be engaged by cam I08 fixed to distributor shaft 3|. The apex of cam I08 extends downwardly of shaft 3| and is arranged to impart counterclockwise movement to resetting lever I06. The orientation of cam I08 with respect to shaft 3| is such that lever I06 will be reset immediately after the transmission of the last code impulse of a code combination, from which it follows that lever I06 will reset blocking lever 86 at about the beginning of the stop impulse or about'the same time that cam I4 seeks to retract bail 6! to extreme counter-clockwise position. The relation of the cam follower portion of lever I06 to its cam I08 is such that the cam follower portion of the lever will be held below and out of the path of the apex of cam I08 when bail blocking lever 86 is held latched by latching lever 9 I, which is the condition shown in Fig. 3, and also will be held out of the path of the apex of the cam when lever 86 is resting upon but not blocking bail 61, which is the condition shown in Fig. 4. However, when lever 06 has dropped into position to block bail 61, which is the condition shown in Fig. 5, the cam follower portion of lever I06 will have been lifted into the path of the apex of cam I08, which has a steep slope for rocking reset lever I06 sharply in counter-clockwise direction. The movement imparted to lever I06 by cam I08 during actual travel of the cam follower portion of the lever along the slope of the-apex of cam I08 to its peak is insufiicient to reengag'e arm of bail blocking lever.

86 with latching lever 9I, assuming that at the time of operation of reset lever I86, electromagnet 92 is not energized, nor is latching lever 9| held in ineifective position by retaining lever 99. In consequence of the sharpness of the movement imparted to lever I 86, it overtravels, due to an inertia effect, sufficiently to reengage blocking lever 86 with latching lever 9I. The pin I20, in moving upwardly as lever 86 is lifted by resetting lever I96, rocks bell crank lever I95 counter-clockwise in order to pass and move into position above the laterally extending arm of the bell crank, whereupon spring I99 restores the bell crank to normal and presents the laterally extending arm in the downward path of pin I29. With this arrangement the position of retaining lever is not disturbed by the upward movement of pin I29, whether lever 90 is in the position shown in Figs. 3 and or is in the position shown in Fig. 4.

When the blocking lever 86 is rocked clockwise by resetting lever I 06, the tip of arm 89 will strike the lower surface of pivoted channel-shaped member I25, assuming that latching lever 9| is then in extreme counter-clockwise position, and will rock it in counter-clockwise until arm 89 slides off the right-hand edge of the lower surface of member I25, whereupon compression spring I39 will restore member I25 to extreme clockwise position in latching relation to arm 89 of lever 83. Thus the position of latching lever 9I is not disturbed. If, instead of having the pivoted latching channel member I25, lever 9! had an integral or rigidly secured latching body, it would be necessary for arm 89 of lever 86 to lift latching lever 9| slightly in order to clear the right-hand edge of the latching body, and due to the fact that lever 86 is lifted sharply, it might in'turn lift latching lever 9| sufiiciently to permit latching projection I09 of retaining lever 90 to move into latching relation to lever 9I, thus creating artificially a condition corresponding to energization of magnet 92, and lever 86 would not become relatched.

The line I1 over which signals are transmitted from transmitting distributor 24 extends through the operating winding of polarized line relay 2! which controls selector magnet III of the recording printer at intermediate station 22 and terminates at the polarized line relay H2 at the west terminal station (Fig. 1). Line relay II2 controls the selector magnet II3 of recording printer I6 by operating the selector lever II4. Under the control of selector lever H4 and of individual sword lever bell cranks I I6 operated by cams H1 in a receiving selector cam assembly, individual sword levers II8 are set in extreme clockwise or counter-clockwise positions and through individual T-levers II9 the sword levers set'individual permutation code bars I2I. Code bars I2I individually select pull bars I22 by presenting individual alignment of notches thereto and upon selection of a pull bar I22 the alignment of notches presented thereto permits the pull bar to be moved by an associated biasing spring into engagement with the base of the alignment of notches, thereby bringing a'shoulder of the pull bar into the path of an operating bail I23. Bail I23 is supported for oscillatory movement by a plurality of posts I24, one of which is shown in Fig, 1.

A driving motor I 26 for the printer I6 is arranged to impart rotation to 'a cam I21 through worm I28, worm wheel I29 and jaw clutch I3I. As is fully disclosed in Patent 1,745,633, granted February 4, 1930, to S. Morton et al., clutch I3I is normally disengaged and is of the single revolution variety. Immediately upon the reception of the last selecting impulse of a code combination, clutch I3I is engaged by means not shown in the present drawing, for rotating cam I21 through one revolution. Cam I21 controls a bell crank I32, permitting the bell crank to be rocked in counter-clockwise direction as viewed in Fig. 1, by its biasing spring I33 and then re-' storing the bell crank to normal or extreme clockwise position. Bell crank I32 is articulated to one of the posts I24 by which operating bail I23 is operated and when spring I33 rocks bell crank I32 in counter-clockwise direction under the control of cam, I21, bail I23 is moved upwardly and imparts upward movement to any one of the pull bars I22 which has been selected and thus had its operating shoulder moved into the path of the bail.

Certain of the pull bars have rack and pinion engagement with individual type bars I34, and as a pull bar I 22 is moved upwardly, its associated type bar I34 is rocked forwardly and downwardly to cause it to print by means of an inked ribbon (not shown) upon a paper tape (also not shown) against the backing of a printing platen I36.

Printing platen I36 is secured to rotatable shaft I31 to which step-by-step rotation is imparted through pinions I38 and I39 from a'shaft 'I4I which has secured thereto a ratchet I42 which is engaged by a pawl I43 carried by a pivoted lever I44. Lever I44 is provided with a roller I46which is normally presented in a cam recess I41 in bail supporting post I24. When post I24 is moved upwardly by bell crank I32 under the control of cam I21 lever I44 is rocked in clockwise direction as viewed in Fig. 1 by the 'cam depression in post I24 to move pawl I43 downward-' ly along the periphery of ratchet I42 to pick up the next tooth. When bail supporting post I24 is restored to normal position by cam I21, lever I44 returns to extreme counter-clockwise position and in being so restored lifts pawl I43- to effect rotation of ratchet I42 througha short angular distance. The rotationof ratchet I42 is transmitted through shaft I4 I, pinions I39 and I38, and shaft I31 to platen I36. Rotation is thus imparted to platen I35 through a correspending angular distance to provide letter spacing advancement of the tape upon which printing is effected. The printer described briefly in the foregoing paragraphs iswell known in the prior art and further detailed description of its cured to the frame of printer I 6 fixedly supports a stationary shaft I52 which has sleeved or journaled thereon a rocker member I53 which is in the form of a plate, or partial disc. Rocker member I53 is provided with a radially extende ing finger I54 which is disposed above and in the path of the heel portion I56 of a special pull bar I51 in printer I6. Special pull bar I51 may have rack and pinion engagement with-a type bar if it is desired to print a special character when special pull bar I51 is selected and operated, but no such type bar has been shown in Fig. 1. It is to be understood however that the special attributes of pull bar I51 and the special function which it is arranged to perform do not preclude the addition thereto of a rack portion for operating a type bar. It will be apparent that when pull bar I51 is selected and is moved upwardly by bail I23, heel portion I56 of the pull bar will engage finger I54 of rocker member I53 and rock the member in clockwise direction as viewed in Figs. 1 and 6. A tension spring I53 biases rocker member I53 into normal position against a stop screw I59 (Fig. 6), and the plunger of a dashpot I60 connected to rocker member I53 by rod I65 has no effect upon the rocking of rocker member I53 clockwise but retards its return to normal under the influence of spring I58.

Rocker member I53 has secured thereto three rods designated by the reference numerals I6I,

I62 and I63 which extend parallel to shaft I52. Rod I6I extends through an elongated slot I64 in a slide member I66 and provides one point of support for the slide member. The other point of support for slide member I66 is provided by a pawl I61 which has a pin I68 disposed in another elongated slot I69 in slide member I66 and which, in turn, is supported by engagement of the upper end of an elongated slot I1I in pawl I61 with a fixed pin I12 which penetrates slot I1I. Pawl I61 is biased by spring I13, which is distended between pawl I61 and slide member I66, into engagement with rod I63. Slide member I66 is biased by spring I19 in counterclockwise direction to seat the upper end of slot "I in pawl I61 upon pin I12.

Rod I62 extends between spaced depending arms I14 of slide member I66 and similar tension springs I16 connect rod I62 to the two arms I14 of slide member I66. Since springs I16 are similar and preferably of equal tension they positionarms I14 of slide member I16 at equal distances from rod I 62 and thus determine a stationary normal position for slide member I 66. It will be apparent that by virtue of slots I64 and IE6, slide member I66 can move longitudinally without disturbing the position of pawl I61. Also, it will be apparent that pawl I61 can rock about its point of support on pin I12 without materially disturbing the elevational position of slide member I66.

Slide member I66 is provided with a lip portion I11 which is disposed adjacent to but normally out of the operating path of a toe portion I18 of special pull bar I51. but is normally held by rod I63 from engagement with a ratchet I8I secured to a sleeve I82 which is rotatably sleeved on stationary shaft I52. A jockey type of detent I83 indexes ratchet I6I into predetermined positions of arrestment and holds the ratchet stationary. Pawl I61 is provided with a retaining shoulder I84 which, when the pawl is rocked clockwise as viewed in Fig. 6, to engage ratchet IBI, and is elevated in a manner which will be described hereinafter to effect rotation of the ratchet, hooks over a stationary bar I86 and holds pawl I61 elevated until the pawl is disengaged from bar I86, as will also be described hereinafter.

Sleeve I82 has secured thereto a cam I81 the periphery of which consists of alternate high and low portions, the total number of which is equal to the number of teeth on ratchet I8I. Cam I81 controls a pair of contacts I88, closing the contacts when a cam follower lug I89 engages a Pawl I61 is aligned with high portion of the periphery of cam I81 and. permitting the contacts to open when the follower lug I89 descends into one of the low portions in the periphery of the cam I61. In successive stepping operations of ratchet I8I, contacts I88 are alternately opened and closed.

One of the contacts I88 is connected to ground and the other is connected to conductor I6I which extends to one of a pair of tape tension responsive contacts I92 in transmitter I 8 associated with the printer I6 at the west station. The other of the contacts I92 is connected by conductor I 93 to one side of a manually operable switch I94, the other side of which is connected to one end of the winding of start magnet I96 for the transmitter I8. The other side of the start magnet I96 is connected to grounded battery I91.

Transmitter I8 which has been shown diagrammatically in Fig. 1 may be similar to the transmitter shown in Fig. 2 and includes as its principal elements, driving motor 26I, friction clutch 282, driving gears 293 and 284, distributor shaft 266, distributor brush arm 291, segmented ring 298, continuous ring 289, stop cam 2H and stop lever 2I2 controlled by start magnet I96. It will be understood that transmitter I8 is provided with tape sensing mechanism controlled by distributor shaft 266 for sensing code perforations in tape 2I3 and setting up the code combination on the segments of segmented ring 208.

Before proceeding with a general description of the operation of the entire system, the operation of the ratchet feed mechanism for operating cam I81 in Fig. 1 will be described. Upon the selection of special pull bar I51 followed by upward movement of the pull bar by bail I23, rocker member I53 will be rocked in clockwise direction, which brings it into the position shown in Fig. 7. The rocking of rocker member I53 is accompanied by displacement of rods I6I, I 62 and I63 about the axis of stationary shaft I52. Rod I6I is moved to the left in slot I64 of slide member I66 without imparting any movement to the slide member. Rod I62, in moving to the left, distends further the right hand of the springs I16, thereby increasing the tension, and correspondingly permits the left hand of the springs I16 to contract, thereby decreasing its tension The springs I16 are thus unbalanced and the right-hand spring seeks to move slide member I66 leftwardly. However, the toe por tion I18 of special pull bar I51, in moving upwardly to rock the rocker member I 53 clockwise, has moved into blocking relation to the lip portion I11 of slide member I66, so that the slide member is at this time prevented from moving leftwardly. The rod I53 is shifted rightwardly from its original position, thereby moving away from pawl I61 and permitting the pawl to rock clockwise into effective relation to ratchet I8I and with its right side resting against retaining bar I36. Since the pawl has not been lifted, the retaining shoulder I84 of the pawl is below the retaining bar I86. This condition of the apparatus is shown in Fig. 7, and toe portion I18 of special pull bar I51 is at the upper limit of its travel blocking the slide member I66.

Since the operation of special pull bar I51 by bail IE3 is only momentary, the pull bar immediately returns to its normal or lower position out of blocking relation to the lip portion I11 of slide member I66. Springs I 16 thereupon undertake to restore to equality the forces which they exert between rod I62 and the depending arms I14 of slide member I66, and they accomplish this by moving slide member I66 leftwardly to present its lip portion I11 above and in the path of toe portion I18 of special pull bar I51. ratchet I8I and with retaining bar I86 is not disturbed as a result of the leftward movement of slide member I66, because slot I69 accommodates the movement. Since the dashpot I66 retards the restoration of rocker member I53 to extreme counter-clockwise position by spring I58, the rods I6I, I62 and I63 will have been shifted only slightly from their fully operated positions at the time that special pull bar I51 has returned to normal position. This condition of the apparatus is shown in Fig. 8.

In order for the ratchet feed mechanism thus conditioned for operation to be operated, special pull bar I51 must again be selected and operated before spring I58 has restored rocker member I53 to normal under the retarding influence of dashpot I60. Assuming that the next received signal also efiects the selection of special pull bar I51, the pull bar will again be lifted to its uppermost position and since not only the arm I54 of rocker member I53 but also the lip portion I11 of slide member I66 are in the operating path of the heel portion I56 and toe portion I18, respectively, of the pull bar, the rocker member I53 will again be rocked to its extreme clockwise position and slide member I66 will be, for the first time, rocked to extreme clockwise position about the rod I6I in slot I64 as a pivot. Since there is no freedom of movement upwardly of slide member I66 independently of pawl I61, the pawl will be shifted upwardly in engagement with ratchet I8I to efiect rotation of the ratchet one step, and this movement of the pawl will bring its retaining shoulder I34 above the upper surface of stationary retaining bar I86. At this time, rod I63 is held clear of pawl I61 because of the second rocking of rocker member I53 into extreme clockwise position, and, accordingly, spring I13 will rock pawl I61 in clockwise direction sufficiently to hook its retaining shoulder I84 over retaining bar I86.

With the advancement of ratchet I8I one step, cam I81 will be advanced one step to permit contacts I88 to open, if they were previously closed, or to close them if they were previously open. The operated condition of the ratchet feed mechanism is shownv in Fig. 9 and the heel and toe portions I56 and I18, respectively, of pull bar I51 are shown in their fully operated positions.

Immediately after the condition of the apparatus shown in Fig. 9 is attained, the pull bar I51 returns to normal position, which is the condition shown in Fig. 10. The return of rocker member I53 to normal position is retarded by dashpot I66, as previously stated, and, accordingly, pawl I61 remains hooked on retaining bar I86 for a brief interval. As rocker member I53 returns to normal position, it carries its rods I 6I, I62 and I63 to their normal position. The rod I63 in moving leftwardly disengages shoulder I84 of pawl I61 from retaining bar I86 whereupon spring I19 restores slide member i556 and pawl I61 to their lowermost positions with the upper end of slot I1! of pawl I61 resting on pin I12. As rod I53 returns to normal it disengages pawl I61 from ratchet NH and as rod I62 returns to normal it retracts slide member The engagement of pawl I61with I66 to its extreme right-hand position with its lip portion I11out of the operating path of toe portions I18 of pull bar I51. Thus the apparatus is restored from the condition shown in Fig. 10 to that shown in Fig. 6. The dashpot I6II is adjusted to prolong the restoration of rocker member I53 to normal postion so that the rocker member cannot restore pawl I61 and slide member I66 from the condition shown in Fig. 8 to that shown in Fig. 6 in the interval between two operations of pull bar I51 in successive cycles of operation of receiving printer |6 (Fig. 1)}. Preferably the restoration time forrocker member I53 as controlled by dashpot I is of the order of one second, and since telegram transmitters and printing recorders of the type shown herein are adapted to operate on a frequency of six permutation codecombinations per second, the rocker member I53 will not re- .turn far enough toward normal position to disengage pawl I61 from ratchet I8I nor to disengage lip portion I11 of slide member I66 from toe portion.|18 of pull bar I51 even if a code for selecting some other elementthan the special pull bar I51 should intervene two selective operations ofthe pull bar I51..

For a consideration of the operation of the system as a whole, it will be assumed that ratchet .controlled contacts I88, tape tension controlled contacts I92 and the manually operable switch I64 in Fig. 1 are closed, from which it follows that transmitter brush arm 201 is rotating continuously to transmit signals under the control of perforated tape 2I3 over com- Ill ' munioation line I9 to the recording printer 26,

which isshown in Fig.2. It will also be as.- sumed-that at the eaststation in Fig. 2, tape tensioncontacts 19 and manually operable switch 82 are closed so that distributor brush arm 26 is operating continuously to transmit permutation codesignals under the control of perforated tape- 51 overcommunication line I1 to recording printer I6 shown-in Fig. 1.

In order for intermediate station- 22 to send a message, which may be of extreme urgency, to the east station in Fig. 2, it is necessary for the intermediate station to be able to interrupt the transmission on communication line I9 from transmitter I8 in order that the intermediate station can-transmit over the communication line I9. Accordingly, intermediate station 22 is .provided with a break key 2I5 in series with the transmitter 23,-which may be opened and held for any desired period. Upon the opening of breakkey 2I5 communication line I9 is interrupted and the line relay I02 andrecording printer 26 (Fig. 2) are placed in steady spacing condition. This causes printer 26 to run open or in: the all-spacingcondition, and pull bar I94 is selected'and operated repeatedlyas long as break 'key'2I5 is held open. The operation of contacts 96 causes magnet 92 to attract its armature-and release bail blocking lever 86, which :falls into engagement with the top of bail 61 if transmitter 24 is then inthe midst of transmissionofa code combination. Latching lever 9| is held in the ineffective position by retaining lever 96. At the end of the transmission of the code by transmitter 24, bail 61 is rocked to extreme' counter-clockwise position by cam 14 and blocking lever 66 drops into blocking relation to bail61, thus setting up an all-spacing signal on the segments of ring 28 of transmitter 24 and disengaging lever from latching lever 6 I. Contacts 98 are also closed, thus short-circuiting tape tension contacts I9 and manually operable switch 82. Therefore, distributor brush arm 29 continues to rotate and transmits a blank signal combination on communication line I1.

Printer I 6 at the west station (Fig. 1) responds to the blank signal combination by the selection of special pull bar I51 which is operated by bail I23 to operate the rocker member I53 to establish the condition shown in Fig. 7 which, upon the return of pull bar I 51 to normal position, changes to the condition shown in Fig. 8.

At some time during the transmission of the blank signal combination from transmitter 24, pull bar I84 in the printer 26 at the east station (Fig. 2) is again operated, since the communication line I9 remains open at key 2I5, to effect a second attraction of the armature of magnet 92, whereupon latching lever 9| again becomes retained in the ineffective position to prevent the bail blocking lever 86 from being relatched as a result of the resetting operation at the end of the first blank signal. Thus, although cam I08 operates resetting lever I06, the bail blocking lever 86 does not become latched by latch 9| but again drops into blocking relation to bail 67 before the bail is released by cam I4 and again retracts the retaining lever 99 to release latching lever 9|. Accordingly, bail 61 remains held in its extreme counter-clockwise position and tape feed bell crank 64 is held stationary so that tape 51 is not advanced and none of the signals contained therein is lost. The transmitter 24 proceeds to transmit on communication line I1, the second blank signal combination.

At the west station, printer I6 (Fig. 1) responds to the second blank signal by again selecting special pull bar I! which operates to change the condition of the ratchet feed mechanism from that shown in Fig. 8 to that shown in Fig. 9 thus efiecting feeding of the ratchet I 8| one step and latching pawl I61 on retaining bar I86. Advancement of the cam I81 one step accompanies advancement of the ratchet I8I, and this advancement is suflicient to move a high portion of cam I81 out of registry with the cam follower lug I89 of contact I88 and to bring a low portion of the cam into registry with the cam follower. Thus the contacts I89 are permitted to open and the energizing circuit for start magnet I96 of transmitter I8 is interrupted. The start magnet I96 releases stop lever 2I2 which moves into the path of stop cam 2| I and arrests distributor shaft 266 of transmitter I8. The transmission of signals from transmitter I8 on communication line I9 has thus been interrupted and the line can be used for transmission by the intermediate station 22.

The break key 2| 5 need be held open only long enough for the transmitter 24 at the east station to effect the transmission of two blank code signal combinations on communication line H. Should it be held open for a longer period so that latching lever 9| is repeatedly lifted and retained, bail blocking lever 86 is repeatedly prevented from being latched, and several blank code signals are transmitted by transmitter 24, the only effect of repeated operation of pull bar I5! (Fig. 1) beyond the second operation thereof will be to delay the restoration of rocker member I53 to normal, since pawl ISI remains held by retaining bar I86 and slide member IE6 is also held in the position shown in Fig. 9.

Upon the reclosure of break key 2|5, the printer 28 will come to rest at the conclusion of the cycle which was in progress when key 2I5 was closed, because message transmission from the intermediate station 22 has not yet started. With printer 26 in the rest condition contacts 95 will remain open and magnet 92 will remain deenergized so that latch 9| will be in position to retain bail blocking lever 66 in unoperated position when the lever is restored to that position by resetting cam I 98 operating through reset lever I66. Since it was originally assumed that tape tension contacts I9 and manually operable switch 82 are both closed, start magnet 4| for transmitter 42 will remain energized after contacts 98 are restored to open condition by the resetting of bail blocking lever 86, and distributor shaft 3| will continue to operate. When cam I4 releases bail 61 preparatory to transmission of the next signal the bail will not be blocked and will accordingly permit the tape sensing levers 54 and tape feed bell crank 64 to operate in the normal manner to resume the transmission of signals on communication line I! under the control of perforated tape 51. The communication line I9 is now in condition for transmission of message material from intermediate station 22, since transmitter I8 has been disabled and station 22 may proceed with message transmission.

At the conclusion of message transmission from intermediate station 22, break key 2| 5 is again opened, or blank signals may be transmitted either from a tape transmitter or by operation of the blank signal key of a keyboard transmitter. As previously described, this will cause contacts 96 in printer 26 to be operated and latch 9| to be operated by magnet 92 to release bail blocking lever 86. The effect of the release of bail blocking lever 85 upon transmitter 24 when the transmitter has been operating under the control of perforated tape 5'! has been previously described, and the eiTect is the same on transmitter 24 whether break key 2I5 has been opened to initiate or conclude transmission from intermediate station 22. Accordingly, it will be assumed for the purposes of the following description that transmission on line I! from transmitter 24 was concluded or interrupted at some time during the transmission of message material from intermediate station 22 to printer 26, by the opening of tape tension contacts 79 due to the taking up of slack in tape 51 or by the manual opening of switch 82. Thus, start magnet 4I will be assumed to be deenergized and stop lever 31 will be holding stop cam 39 arrested with cam 14 holding bail 6'! in extreme counterclockwise position.

Upon the first operation of pull bar I94, latch 9| releases blocking lever 86 which immediately drops into blocking relation to bail 61, trips off the retaining lever 99 for the latching lever 9| and closes contacts 98. The contacts complete an energizing circuit for start magnet 4| shunting the contacts I9 and switch 82, one of which is assumed to be open, and brush arm 29 of distributor 24 is released for rotation to transmit the blank signal. At the west station (Fig. l) printer I8 responds by operation of pull bar I51 to change the ratchet feed apparatus from the condition shown in Fig. 6 to that shown in Fig. 7, and on the return of the pull bar to normal position, the apparatus is changed to the condition shown in Fig. 8. At the end of the transmission of the blank signal combination, reset lever I96 is operated to attempt to reset blocking lever 86, but magnet 92 is again energized due to response of the pull bar I04 to the open line condition of line l9 and blocking lever 86 is not resetbut again drops into blocking relation to bail 6'1. Contacts 98 are again closed and distributor shaft 3! is released for the transmission of another blank signa1 combination. The printer I6 responds to this blank by operation of special pull bar 15'! to change the ratchet feed mechanism from the condition shown in Fig. 8 to that shown in Fig. 9, in the course of which change paw1 I67 operates ratchet l8! one step. Cam I81 is thus advanced one step to efiect the reclosure of contacts I88, whereby the energizing circuit of start magnet I96 of transmitter I8 is completed and the magnet is energized to restart transmitter I8.

Upon the reclosure of break key 2|5, the cyclic operation of pull bar 104 in printer 25 (Fig. 2) ceases and blocking lever 86 is reset by reset lever I06 at the end of the transmitting cycle of transmitter 24 then in progress. With the resetting of lever 85, contacts 98 open and with contacts 19 or manually operable switch 82 open as previously assumed, the transmitter 24 will be stopped. Upon the reclosure of break key 215, the circuit or communication line 49 i completed and the signals generated in transmitter 18 will be received by printer 26.

Reference was previously made to the possibility of providing a type bar to be operated by the special pull bar l? and the provision of such a type bar with a special type character to be printed may be advantageous. It will be apparent that upon the opening of break key 2H5 at station 22 for the purpose of interrupting transmission from transmitter 18, the transmitter will continue to operate until special pull bar I51 has been operated twice to effect the arrestment of transmitter l8. Also, when transmitter i8 is restarted due to the opening of break key 2i5 at the conclusion of transmission from station 22, if the operator at station 22 holds key 215 open longer than the time necessary for special 'pull bar I51 to be operated twice, any signals generated by transmitter 18 will be lost because of the open condition of line 19. The typing of the special character by a type bar associated with special pull bar l5! will serve as a warning to an operator at the west station to back space the tape 213 in transmitter I8 sufficiently to compensate for the loss of signals due to operation of the transmitter while break key 215 at the intermediate station 22' is open. The special pull bar I51 might also be arranged to operate an alarm such as a signal bell in accordance with well known practices to attract the attention of an operator to the fact that the transmitter is being interrupted and subsequently that the transmitter is being restarted so that any necessary readjustment of tape 2 E3 in transmitter l8 may be made.

It will be noted that the system as shown includes no provision for transmission of messages from the west station to the intermediate station 22 nor for transmission of messages from the" intermediate station 22 to the west Sta-- tion. The reason for this is that the west station and the inter-mediatestation may be assumed to be subordinate to the east station and there is little or no occasion for transmission between the subordinate stations. This being the case, an operator at station 22 has no means for determining whether or not the West station is transmitting to the east station and therefore should always precede transmission which he desires to initiate by operating break key 215 to effect the arrestment of transmitter l8 if it should happen to be their operating. Similarly; the operator at station 22 should always operate break key 215 at the conclusion of transmission from station 22 to printer 26 as, otherwise, transmitter [8 would be left in disabled condition due to the fact that contacts I 88 remain open.

If it should be desirable to provide for intercom-munication between the west station and the intermediate station, this may be accomplished by adding at station 22, in series with line relay 2!, a set of transmitting contacts to be controlled either by a keyboard mechanism or a tape transmitter mechanism and by adding in series with the transmitter 23 at station 22 the line relay of a printer. The transmitter added in series with line relay 2| could then be operated to transmit signals to printer IE but could only be operated at a time when messages were not being transmitted over line I! from the east station. By the addition to the printer represented symbolically by the selector magnet III at station 22 of a ratchet feed transmitter controlling mechanism similar to that associated with the printer l8, transmitter 24 at the east station, by the transmission of signals over line H, could interrupt transmission from station 22 to the west station in order to permit transmitter 24 at the east station to transmit to both of the printers associated with line H. The added transmitter controlling mechanism could be made responsive to some signal other than blank whereby transmission from intermediate station 22 to the west station could be interrupted under the control of the transmitter at the east station without interrupting transmission from the west station to the east station over communication line iii. The addition of a printer controlling line relay in series with transmitter 23 at station 22 would not only provide means for recording signals received from transmitter [8, but would also provide at station 22 a home rec 0rd of signals transmitted from station 22 to the printer 26 at the east station.

Although a specific embodiment of the invention has been disclosed in the drawings and described in the foregoing specification, it is to be understood that the invention is not limited to such specific embodiment :but is capable of modification, rearrangement and addition or substineous two-way transmission, a third station associated with said channel intermediate the firstmentioned stations having a telegraph transmitter for transmitting telegraph signals to the re.- ceiver at one of the stations and having a telegraph receiver for receiving telegraph signals from the transmitter at said one station, means at the intermediate station for interrupting transmission to the receiver at the station to which said intermediate station is arranged to transmit, means operated by said receiver in response to the interruption of transmission for conditioning its associated transmitter to transmit a predetermined signal repetitiously, and means controlled by the receiver at theother end of the channel responsive to the predetermined signal for disabling the transmitter associated therewith.

2. In a telegraph system, a station having a telegraph receiver and a telegraph transmitter, another station having a telegraph receiver and a telegraph transmitter, a communication channel connecting the transmitter of each station to-the receiver of the other station for simultaneous two-way transmission, a third station associated with said channel intermediate the firstmentioned stations having a telegraph transmitter for transmitting telegraph signals to the receiver at one of the stations and having a telegraph receiver for receiving telegraph signals from the transmitter at said one station, means at the intermediate station for interrupting trans mission to the receiver at the station to which said intermediate station is arranged to transmit, means operated by said receiver in response to the interruption of transmission for conditioning its associated transmitter to transmit a predetermined signal repetitiously, and means controlled by the receiver at the other end of the channel responsive to a plurality of said predetermined signals for disabling the transmitter associated therewith.

3. In a telegraph system, a station having a telegraph receiver and a telegraph transmitter, another station having a telegraph receiver and a telegraph transmitter, a communication channel connecting the transmit-ter of each station to the receiver of the other station for simultaneous two-way transmission, a third station associated with said channel intermediate the first-merrtioned stations having a telegraph transmitter for transmitting telegraph signals to the receiver at one of the stations and having a telegraph receiver for receiving telegraph signals from the transmitter at said one station, means at the intermediate station for opening the communication channel to interrupt transmission to the receiver at the station to which said intermediate station is arranged to transmit, means operated by said receiver in response to the opening of the communication channel for interrupting the transmission of message material from its associated transmitter and for conditioning said transmitter to transmit a predetermined signal repetitiously, means controlled by the receiver at the other end of the channel responsive to a plurality of the predetermined signals for disabling the transmitter associated therewith, and means operable in response to restoration of said communication channel to normal condition for restarting transmission of message material from the transmitter which transmitted the predetermined signals.

4. In a telegraph system, a station having a telegraph receiver and a telegraph transmitter, another station having a telegraph receiver and a telegraph transmitter, a communication channel connecting the transmitter of each station to the receiver of the other station for simultaneous two-way transmission, a third station associated with said channel intermediate the first-mentioned stations having a telegraph transmitter for transmitting telegraph signals to the receiver at one of the stations and having a telegraph receiver for receiving telegraph signals from the transmitter at said one station, means associated with the transmitter at the intermediate station for interrupting the porion of the communication circuit extending to the station to which said intermediate station is arranged to transmit, means operated by said receiver in response to the opening of the communication channel extending thereto for setting in operation its associated transmitter to transmit blank signals repetitious-- ly, and means controlled by the receiver at the other end of the channel responsive to the blank signals for disabling the transmitter associated therewith.

5. In a telegraph system, a station having a telegraph receiver and a telegraph transmitter, another station having a telegraph receiver and a telegraph transmitter, a communication channel connecting the transmitter of each station to the receiver of the other static-n for simultaneous two-way transmission, a third station associated with said channel intermediate the firstmentioned stations having a telegraph transmitter for transmitting telegraph signals to the receiver at one of the stations and having a telegraph receiver for receiving telegraph signals from the transmitter at said one station, means at the intermediate station for interrupting trans mission to the receiver at the station to which said intermediate station is arranged to transmit, means operated by said receiver in response to the interruption of transmission for initiating the transmission by its associated transmit ter of a predetermined signal and for preventing the transmission therefrom of miscellaneous message material, and means controlled by the receiver-at the other end of the channel responsive to the predetermined signal for estopping operation of the transmitter associated therewith 6. In a telegraph set including a receiver and a transmitter, said transmitter including means operable under the control of a message record storage medium for setting up signals and a distributor for transmitting said signals, means for operating said signal setting up means to set up a predetermined signal independently of said message record storage medium, means for retaining said setting up means operated to set up said predetermined signal, and means controlled by said receiver for rendering said retaining means effective.

7. In a, telegraph set including a receiver and a transmitter, said transmitter including means operable under the control of a message record storage medium for setting up signals and a distributor for transmitting said signals, means for operating said signal setting-up means to set up a predetermined signal independently of said message record storage medium, means for retaining said setting -up means operated to set up said signal, means controlled by said receiver for rendering said retaining means effective, and cyclically operable means for disabling said retaining means.

8. In a telegraph set including a receiver and a transmitter, said transmitter including means operable under the control of a message record storage medium for setting up signals and a distributor for transmitting said signals, means for operating said signal setting-up means to set up a predetermined signal independently of said message record storage medium, means for retaining said setting-up means operated to set up said signal, means controlled by said receiver for rendering said retaining means effective, and means operable cyclically by said distributor for disabling said retaining means.

9. In a telegraph set including a receiver and a transmitter, said transmitter including means controlled by a signal storing instrumentality for setting up combinations of marking and spacing signals and a distributor for transmitting said signals, means actuated by said distributor for cyclically operating said signal setting-up means to set up an all-spacing signal, means for retaining said setting-up means in the all-spacing signal condition, means controlled by said receiver for rendering said retaining means effective, and means operable cyclically by said distributor for disabling said retaining means.

10. In a telegraph set including a receiver and a transmitter, said transmitter including means for cooperating with a signal storing medium to set up combinations of marking and spacing signals and a distributor for transmitting said signals, means controlled cyclically by the distributor for retracting said setting-up means from cooperation with said signal storing medium and into position for setting up an all-spacing signal, means controlled by said receiver for retaining said setting-up means out of cooperation with said signal storing medium and in position to set up said all-spacing signal, and means actuated cyclically by said distributor for momentarily disabling said retaining means.

11. In a telegraph set including a receiver and a transmitter, said transmitter including means for setting up signals and a distributor for transmitting said signals, means for conditioning said signal setting-up means to set up a predetermined signal, means for retaining said setting-up means conditioned to set up said predetermined Signal, meanscontrolled by said receiver for rendering said retaining means effective, and means operable cyclically only when said retaining means has been in effective position for disabling said retaining means.

12. In a telegraph set including a receiver and a transmitter, said telegraph receiver including a signal responsive selector mechanism and a plu rality of selectable elements, means responsive to a plurality of successive cyclic operations of one of said selectable elements for alternately stopping and starting said transmitter, means for limiting the operation of said stopping and starting means to one stopping or starting operation in response to a succession of cyclic operations of said one selectable element, and-means for subsequently disabling said limiting means.

13. In a telegraph set including a receiver and a transmitter, said telegraph receiver including a signal responsive selector mechanism and. a plurality of selectable elements, means responsive to a plurality of successive cyclic operations of one of said selectable elements for alternately stopping and starting said transmitter, means for limiting the operation of said stopping and starting means to one stopping or starting operation in response to a succession of cyclic operations of said one selectable element, means for restoring said stopping and starting means to normal position, means for retarding the restoration of said stopping and starting means to normal position, and means operable incident to the restoration of said stopping and startin means for disabling said limiting means. 14. In a telegraph set including a receiver and a transmitter, said telegraph receiver including a signal responsive selector mechanism and a plurality of selectable elements, conditioning means operable by one of said selectable elements, means for restoring said conditioning means to unoperated condition, means for retarding the restoration of said conditioning means, means conditioned by said conditioning means to be operated by said one selectable element in the next operation thereof, ratchet feed means opermeans to unoperated position, means for retarding the restoration of said conditioning means to normal position, means normally dissociated from said one selectable element to be conditioned by said conditioning means to be operated by said one selectable element if said selectable element is again selected and operated before the restoration of said conditioning means to normal position, ratchet feed means operable by said conditioned means, and means operable by said ratchet feed means for stopping and starting said transmitter alternately in response to successive operations of said ratchet feed means.

16. In a telegraph set including a receiver and a-transmitter, said telegraph receiver including a signal responsive selector mechanism and a plurality of selectable elements, conditioning means operable by one of said selectable elements, means for restoring said conditioning means to normal position, means for retarding the restoration of said conditioning means to normal position, means conditioned by said conditioning means to be operated by said one selectable element, ratchet feed means operable by said conditioned means, means operable by said ratchet feed means for stopping and starting said transmitter alternately upon successive operations of said ratchet feed means, means for retaining said ratchet feed means in operated condition, and means operable by said conditioning means upon the return thereof to normal position for restoring said ratchet feed means to normal condition.

1'7. In a telegraph set including a receiver and a transmitter, said telegraph receiver including a signal responsive selector mechanism and a plurality of selectable elements, conditioning means operable by one of said selectable elements, means for restoring said conditioning members to unoperated position, means for retarding the restoration of said conditioning means to unoperated position, a pawl and ratchet mechanism operable by said conditioned means, means operable by said pawl and ratchet mechanism in one operation thereof for stopping said transmitter and in the next operation thereof for starting said transmitter, means for retaining said conditioned means and said pawl in operated position, and means operable by said conditioning means upon the restoration thereof to unoperated position for restoring said pawl and said conditioned means to unoperated condition.

18. In a telegraph set including a receiver and a transmitter, said telegraph receiver including a signal responsive selector mechanism and a plurality of selectable elements, a rocker member operable by one of said selectable elements, means for restoring said rocker member to unoperated position, means for retarding the restoration of said rocker member to unoperated position, a pawl and ratchet mechanism, apawl operating member associated with said pawl and ratchet mechanism, means yieldably interconnecting said rocker member and said pawl operating member for moving said pawl operating member into position to be operated by said one selectable element, means for retaining the pawl of said pawl and ratchet mechanism and through it said pawl operating member in operated condition, means operable by said pawl and ratchet mechanism in alternate operations for stopping said transmitter and in intervening operations for starting said transmitter, and means carried by said rocker member for releasing said pawl and said pawl operating member for restoration to unoperated position upon restoration of said rocker member to unoperated position.

19. In a telegraph signal transmitter, a signal storing medium, means for sensing the signals in said medium, a start-stop signal generating distributor having impulse segments, a start magnet energizable to cause said distributor to operate, means controlled by said sensing means for applying signaling potentials to said segments, means for advancing said storing medium, means controlled by said distributor for operating said sensing means and said advancing means, means for causing said distributor controlled means to withhold said sensing means and said advancing means, and means controlled by the lastmentioned means for completing the energizing circuit of said magnet.

20. In a telegraph signal transmitter, a signal storing medium, means for sensing the signals in said medium, a start-stop signal generating distributor having impulse segments, the start magnet energizable to cause said distributor to operate, means controlled by said sensing means for applying signaling potentials to said segments, means for advancing said storing medium, means controlled by said distributor for operating said sensing means and said advancing means, means for causing said distributor controlled means to withhold said sensing means and said advancing means, means responsive to the presence of signals in said storing medium for completing the energizing circuit of said magnet and responsive" applying signaling potentials to said segments,-

means for advancing said storing medium, means controlled by said distributor for operating said sensing means and said advancing means, means for causing said distributor controlled means to withhold said sensing means and said advancing means, means responsive to withholding of said sensing means for completing the energizing circuit of said magnet, and means also responsive to withholding of said sensing means for applying to said segments potentials representing a predetermined telegraph signal.

22. In a telegraph signal transmitter, a signal storing tape, a plurality of sensing levers for sensing the signals in said tape, a start-stop signal generating distributor having impulse segments, a start magnet energizable to cause said distributor to operate, transmitting contacts controlled by said sensing levers for applying signaling potentials to said segments, means for advancing said tape to present signals contained therein successively to said sensing levers, a cam associated with said distributor, means controlled by said cam for cyclically retracting said sensing levers and operating said tape advancing means, selectively operable means for blocking said cam controlled means in the operated condition thereof and for holding said cam controlled means in said condition independently of said cam, means controlled by said blocking means for completing the energizing circuit of said magnet to cause said distributor to continue to operate, and means for causing said transmitting contacts to impress on said segments a particular signal for repetitious transmission during the withholding of said sensing levers.

23. In a telegraph transmitter, a rotatable distributor having impulse segments, driving means for said distributor, an electromagnet energizable to permit operation of said distributor and releasable to arrest said distributor, a signal storage tape, a plurality of sensing levers for sensing the signals in said tape, means for advancing said tape to present successive signals therein to said sensing levers, signaling contacts associated with said sensing levers for applying signaling potentials to said segments, a cam associated with said distributor, a bail operable by said cam for retracting said sensing levers from signal sensing relation to said tape and for operating said tape advancing means, and releasable by said cam to restore said sensing levers and said tape advancing means, selectively operable means for blocking said bail in the operated position whereby to render said bail unresponsive to said cam, means controlled by said blocking means for completing the energizing circuit for said magnet, and means for causing said transmitting contacts to apply signaling potentials representing a predetermined signal to said segments for repetitious transmission by said distributor during blocking of said bai1 by said blocking means.

24. In a telegraph system, a pair of stations each having a start-stop telegraph signal transmitter and a start-stop telegraph signal recorder, a telegraph signal channel extending between said stations and accommodating simultaneous two-way transmission between said stations, at least one of said transmitters being of the storage type and including storage signal sensing mechanism, transmitting contact mechanism controlled by said sensing mechanism, storage medium advancing mechanism, a distributor having segments adapted to receive signaling potentials from said contact mechanism and having means for cyclically operating said sensing mechanism and said advancing mechanism, selectively operable means for withholding said signal sensing means and said storage medium advancing means against operation by said cyclically operable means, means for causing said distributor to continue in operation during said withholding, and means for causing said contact mechanism to impress on said segments potentials representing a predetermined signal for repetitious transmission during said withholding.

ARTHUR WILLIAM KAUFMAN.

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