US2361115A - Keyboard operated code transmitter - Google Patents

Description

Oct. 24, 1944. R! MATHES 2,361,115

KEYBOARD OPERATED CODE TRANSMITTER Filed Feb. 5, 1942 Z SheetS-Sheet 1 INVENTOR ATTORNEY Oct. 24, 1944. R MATHES 2,361,115

KEYBOARD OPERATED CODE TRANSMITTER Filed Feb. 5, 1942 Z SheetS-Sheet 2 VE'N OR ATTORNEY Patented Oct. 24, 1944 KEYBOARD OPERATED CODE TRANSMITTER Richard E. Mathes, Westfield, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application February 5, 1942, Serial No. 429,648

12 Claims. ,(Cl.178-80) This invention relates to keyboard transmitters for telegraph systems and more particularly to a transmitter of the type which is adapted to transmit synchronized signals.

In ordinary start-stop keyboard transmitters no continuous synchronization is required between the transmitting and receiving stations since the cyclic transmission of each code signal as initiated at the transmitter is closely enough followed by the speed of operation of the receiving instrumentality. The keyboard transmitter which constitutes the subject matter of the instant invention, however, is one which transmits the code signals for each character in a predetermined time relation to the operation of a time division simplex or multiplex distributor. Such a distributor may be run continuously and'a receiving distributor can be maintained in synchronism with the transmitting distributor by well known means.

In the synchronized signal transmission systems for which my invention is best adapted to be used there is no provision for operating printers on the start-stop principle. For this reason transmission is normally effected by perforating a transmission tape with the desired signals.

- Tape perforators for this purpose have been known in the art for a considerable time. One embodiment of such a perforator is described in a book entitled Printing Telegraph Systems and Mechanisms by H. H. Harrison, published by Longmans, Green 8: Company. On page 167 of this book is a brief description of a similar known keyboard perforator, reference being made to Fig. 165 on page 166. Thatis a perforator of the so-called "Morkrumf system.

One of the disadvantages of using perforated tape for signal transmission is that'a certain delay in' the transmission itself must of necessity occur after the tape has been perforated. This fact is due to the impracticability of immediately utilizing the tape perforations for transmission after a given portion of the tape has been punched by the keyboard. For certain types of springs in association with a synchronous dis-1 tributor.

It is, therefore, an object of my invention to provide modifications of a keyboard perforator such as will provide for direct transmission, not from the perforated tape, but from contact springs directly controlled by the keyboard.

It is another object of my invention to pro-- vide a combination of direct keyboard transmitter and tape perforator such that, when messages have been transmitted by direct keyboard operation, a perforated tape shall simultaneously have been prepared for record purposes at the transmitting station and for repeating the messages, if necessary.

Other objects and advantages of my invention will be made apparent in the more complete description to follow. This description is accompanied by drawings to which reference will be made for a clearer understanding of the invention. In the drawings:

Fig. 1 shows in perspective certain component parts of a keyboard perforator and transmitter sufficient for a clear description of my invention; and

Fig. 2 shows a circuit diagram of the connections which in a preferred embodiment of my invention are necessary to establish operating communication and classes of traflic such delays I -signals by direct control ofcertain code contact association between a keyboard transmitter and a synchronous transmitting distributor.

Referring to Fi 1, I show therein a key bar I!) which is only one, of course, of the entire group of key bars of the keyboard. This key bar is pivoted at H and carries a code selector comb l2 which may beafiixed thereto in any suitable manner, as, for example, by rivets l3. The selector comb may, however, be welded on if desired; or in certain instances itmay be formed integrally with the key bar. Beneath the comb I2 is an arrangement of loop bails P, andl to I inclusive. The bail P is actuated by each and every key and has the function of actuating a certain lever system which stores and locks a given set-up'of contacts, together with associated punch levers, until transmission-of the selected code signal has been effected. In the embodiment shown the function of the bail P is modified with respect to its normal function in the conventional keyboard perfora'torf That normal function heretofore has been to close a contact of a switch for electromagnetically driv ing the punch hammer and the" tape feed device of the perforator. As will be hereinafter explained, the electromagnet for actuating the punch and tape feed device according to my insprings 31 are attached. 7

vention is controlled by a local circuit closed periodically at a particular phase of rotation of the transmitting distributor.

The loop bails l to l inclusive serve when they are actuated for immobilizing their respective punches and simultaneously for opening corresponding contacts of the signal code composing circuits. These loop. bails are allpivoted on the pivot rod 9. Above this pivot rod the bails extend upwardly, these extensions being indicated 1 at M.

are of variable height, but each is notched for- Certain shoulders on the extensions l4 engagement with a bell crank I 5. There-are seven of these bell cranks, each corresponding with one of the elements of a 'Z-uriit codesignal. They areall mounted on a'vertical pivot'rod l6. On this same pivot rod is also mounted a lever arm 26 which engages with a notch in the ve'r-f tical extension 21 operable from and -by the.

. pointedly beyond the linkage centers ll. These pointed ends are arranged to be engaged by. a wedge-shaped member 28 which is movable forwardly and backwardly in order to provide a lock forstoring the set-up of each signal until after it has been transmitted.

The forward ends of the bell cranks are pivotally connected at H to control armslB which extend within the assembly consisting of a die and stripper plate, punch block, guide plate, shedder, and shedder wearing strip, shown generally at IS. The details'of construction of this assembly are not herein described. since they are well known in the art. e 7

According. to .my invention the conventional loop bail extensions 14 are still tfurther extended in vertical portions =29 all of which reach an equal height. At the top of each extension 29 and bearing against the backedge thereof are irisulation blocks 38 supported by contact springs 3 ton which is normally pressedintocontact with a bus bar 32. This bus. bar- 32 is connected with a contact33 (as shown in Fig. 2) and, when any vcombination of thebell cranks is actuated,

connection isn ade between the contact 33 and acontact spring 34. .The latter is-supplied with signalling energyfrom any'suitable source, here indicated as the positive terminal of such a source, the negative terminal being vunderstood to be grounded. Actuation of the spring 34 is obtained by pressureof a pluralityof bell cranks I5 against the vertical actuating bar 35. When this bar is not actuated current is supplied through the contact 34 tothree back contacts 36 whichare used for transmission of a blank? signal. This signal is not used for typewriter spacing, but fills in the signalling time of the transmitting distributor whenever the keyboard operator fails to actuate his 1 keys in step with the distributor. This'conditio will ice-discussed hereinafter.

The wedge-shaped member 28 terminates above and below in abackwardgextension to which These springs 'are drawn rearwardly by attachment to the pivot rod H3. The member 28 is also Suitably held in place byguides (not shown) but it is free toislide for-;

moving levers-39 in a direction to drive the wedgeward and backward. The springs 3! tend to pull it backwardly.

I have also provided sets of levers 38 and 39 for the purpose of forcing the member 28 into its forward position. Lever 38 is pivoted at 40, whereas lever 39 is pivoted at 4!. The punch hammer 2| is of conventional construction. The lever 38 is arranged with'a: forwardly projecting hook 38a sothat when 'the punch hammer 2| is moved forwardly lever 38 will rotate though a small angle about the pivot center 40, thereb;

member 28 forwardly and out of engagement with the pointed ends of the bell cranks l5. Although) the .retu rnXback) stroke of the punch hammer12'l "follows its forward stroke immediately upon deenergization of the operating magnetiZi, I have arranged to lock the wedge-member. 28. forwardly in dependence upon deenergization of the punch hammer magnet 25 and to unlock thewedge-member 23 in dependence upon a subsequent actuation .of a keylllu- The mechnism for accomplishing-this.includes lever arms 26 and 42, the latter being horizontally pivoted-at 43. One end of the lever 42 is tapered and fits under the lever,25. The other end of lever 42 has ashoulder on the'under sideto fit over the end of the backward extension 28a which is integralwith the wedge-member 28. It will be" clear from the perspective view'of F-ig. 1 that priorto a. key depression the back edge of the eXtensiOnZila will rest in. the recess under the end'of leverf'42." This'forward end of lever 42 is raised upon key depression, at which time bail Poperatesft'o move lever 26 against the tapered slope at the back end of lever 42; Then the springsjSl'areallowedto'contract, thus draw- Each contact spring-3| hasacontact but- 1 mg the wedge member 28 backwardly into en'- gagem'ent with'the pointed ends of the bell cranks 15. This looks thesebell'cranks' in whichever position they have been setby key depression. Unlocking takes place 'only' after the wedgememberzll has been removed (forwardly) from engagementjwiththe bell crank levers, that is, upon actuation .of thepunchjmagnetzh At this moment the forward end of lever 42 is allowed to drop by gravity (aidedby a" spring if desired) so that the underlyingshoulder near the end of this lever will engagewith th'eback edge 'of the extension 23a. This. engagement locks the wedge-member 28 in its forward position of disengagement with thejbellcranks "untilsuch time as a'subsequent key is depressed.

' In the operation of "inyinvention a message to be transmitted 'is both perforated on the tape 58 and is caused'to set up -code combinations'for each depression of oneof the keys In of the keyboard.- According (to the 7 unit code system, which'is preferably used in connection with'my keyboard transmitter, each key depression causes three and? onlythree'holes to be 'punched in the tapeby withdrawing selected ones; fo'ur in number, of the levers fll from the' p'ath of the punch lever 2l opposingres'pective punches with: in the punch block assembly lm I Each key when depressed selects for actuation suitable ones of the bails I to linclusive, four in number, not only-to'actuate the' bell cranks l5, but also to-openfour selectedcontacts on-the springs .3.-|,leaving.tonlyathree' of these in engagement with thebus bar- 32h -Tlie actuation of the extension pieces'ZHIOn the-upstandingextensions I4 for codeccomposing purposes hasalreadybeenexplained; 7* .1

In Fig. 2 it .Will beobserived-i that each :or the contact springs 3| is connected directly or indirectly with certain segments 5| of a rotary distributor. The distributor itself is shown in developedform. Associated with the segments 5| is abus ring 52 which is connected to transmitting equipment of any suitable type, such asa keying circuit for a radio transmitter. Assuming that the brush 53 rotates at a predetermined transmission speed as controlled by synchronizing impulses, the code combinations will obviously be collected bypassage of this brush 53 successively over the respectivev segments 5|. Thus, each code combination will be immediately trans. mitted upon depression of its appropriate key.

The operation of the keyboard to perforate the tape is also performed in a conventional manner. In order to permit the transmission of a.suc-, cession of code impulses substantially without ine terruption it is necessary to store at least a portion of each code signal in a storage device'such as shown at 54. The details of this storage device are not herein given since reference may be made to a similar storage device described inan application of James A. Spencer, Serial No. 357,109, filed September 17, 1940, now Patent No. 2,327,075, granted Aug.,1'7, 1943. Reference is here made to Fig. 1 of that application for showing how a part of the code signal may be electromagnetically stored and subsequently transmitted in proper sequence with respect to the code elements for which direct connections are made between the transmitting contacts and the distributor.

In conformity with Spencers system aforementioned, I show individual circuits between contacts 3| and the first four segments of the distributor ring 5| (Fig. 2), while the remaining contacts 3| are connected to the windings of appropriate storage relays (not shown) in the device 54. These relays are locked up automatically upon completing their operating circuits through the contacts of a timing relay under control of an impulse from source 51 through bus ring 55 and segments (12 and d3 which feed conductor 59 when swept over by brush 56. The same storage relays possess contacts through which impulses are transferred to the 5th, 6th, and 7th segments of distributor ring 5|, for completing the transmission of each code combination. At the commencement of the next revolution of the brush 55, a clearing relay (not shown) is actuated for unlocking the three storage relays. This actuation takes place upon passage of brush 56 over segment (11. It will thus be seen that these relays constitute means for introducing a hang-over of effects produced by the closing of the contacts 3| so that the code bars operated by the keys l0 may be returned to normal and the contacts 3| opened even before the brush 53 has traversed the segments5| connected tothe storage device 54.

The actuation of the punch magnet 25 is accomplished by means of a local circuit closed by brush 56 passing over segments ds and d6, this function being thus timed to follow the scanning of the code elements as set up on the contacts 3|. The code signals are thus perforated in the tape while they are being transmitted to the keying circuit. Furthermore, the operation of the punch hammer 2| causes the wedge-member 28 to be driven into a position of disengagement from the pointed ends of the bell cranks I5. The bell cranks are then free to be restored to normal positions. A subsquent key depression causes another combination of hell cranks l5 to be moved across the apex of the wedge-member 28, and

since the-latter is also release'dby lever '-42, the bell cranksare locked in their actuated positions until the next energization of the punch magnet 25.

Should the operator depress two keys within a single 'cycle of the distributor, it is truethat an improper signal might be transmitted. Such a'signal, however, would contain more than three marking elements, and, in accordance withthe prevailing practice in the-use of a 7-unitcode signal system, such erroneous signal would be indicated by an error indication. All correct-signals will be understood. therefore, to consist of three marking elements. .v

For continuous sending the keyboard must be operated in cadence with the local pulses through the brush 56 andsegment-55-of the distributori However, as this is difficult for operators and re-' quires highly specialized training, I h'avepro vided for a blank signal to be transmitted wheneverthe operator skips a beat of the op eratingmagnet 25. This is the purpose of the threecontacts 36 which engage with the contact spring 34'. When the contact spring '34 engages with contacts 35 no current is supplied to the bus bar 32; hence in the-absence of-key depression a code signal consisting ofthree elements in the fifth, sixth, and seventh positions, for example, will be transmitted throughcontacts36 and associated segments 5| of the distributor. The receiving printer performs nooperatingfunction when this blank signal is-received, butth fact that the signal is composed of three marking units permits the error detector to count it as correctly received and therefore no error designating symbol will be printed as would be the case upon reception of a mutilated signal. f

It will, of course, be understood by those skilled inthe art that modifications'of my invention may be made without departing from the spirit.

thereof.

I- claim:

1. A keyboard-operated code signaling device having in combination, a set of keys arranged in a keyboard, a tape perforator having code punches selectively operable under control of the keyboard keys, means including a continuously driven transmitting distributor for timing the operation of punching code elements in a tape and for suc-' cessively transmitting the several code "elements of each character signal selected by said keys, a plurality. of contact devices arranged for selective actuation by said keys in accordance with code signals to be transmitted, and in agreement with the code elements to be punched'in said tape,'and' means for causing the code elementsof each signal to be punched in said tape during the time occupied in transmitting the same signal from said contact devices through said distributor to a telegraph channel.

2. The method of utilizing the keyboard or a 4 permutations of holes to bepunched' in a tape, locking means. operable upon each key depression lforl momentarily storing successive settings :of

said selective means, continuously operable distributormeans for effecting :successiveutransmission of; the codegelements of veach,signal-, lmeans electrically in circuit .withsaid distributor means and. Operable under control of said key.-

bars and bails forcomposing vthexcode elements of each signal, and means a periodically operable by said distributor-.meanslfor causing each signal permutation so, ,cornposed to be transmitted through said distributor. and :for: simultaneously perforating the code elements of the samesignal insaid tape. a.

4.-In-a keyboard transmitter, a group of code element contactors normally held infmarking positions and selectively settable to spacing positions in accordance with the spacing units of a code signal, an assembly of keys, keybars, code element bails selectively operable-by the keybars,and lever mechanism for selectively setting said contactors, acontinuously operable distributor having segments corresponding to said contactors, means for efiectingthe transmission of a code signal throu h said contactors and said distributor'segmentsin response to the actuation of an appropriate key, and. tape perforator means settable by said keys and operable'in cyclic accord with said signal transmitting means for storing in tape a code' -combination of perforations corresponding with the marking elements of the transmitted signal.

5,111 atransmitter of thetype d efinedby claim 4, means operable by the keys of the keyboard for locking selected ones of said contactors in open dence with the cyclic operation of said distributor,

for transmitting a .blank signal through said distributor. 1 t f 7 In a telegraph system which requires the use of, a keyboard operated tape perforatorzand a transmitting distributor having segmentsicorrespending. to the code elements of thesignals and other segments serving to rhythmically control the operations of the system, the method which compiiseslrunning said distributor continuously, manipulating .the keys of the keyboard to set up each combination of .code elements-according to selected characters, causing certain. impulses-representinga portion of each said code combination to be sent out from appropriate segments of said distributor, momentarily storing another portion of. said code combination and. causing the impulses thereof tobe likewise sent out from appropriate segments of said distributor, causing an impulse through at least one of said operationcontrollingsegments to actuate. the perforator thereby to punch holes in the ,tapecorresponding to the code signal then being transmitted, and

8..I n.a keyboard-controlled system fortrahsmittinguniform length character signals through permutationally selected contacts and through corresponding segments :of. a continuously operable distributor, and iorsim'ultaneously perforating. a tape in accordance with said character signals,- the method which comprises manipulating t e keys of said keyboard, causing such manipulation .tomomentarily store the code elements of each successive character signal, causing 'the transmission of saidsignals to. be timed by the cyclic operation of said distributor, causing the storage. of said code elements to cease at a particular cyclic phase of operation of said distributor; and effecting the perforation of each code vsignal'in said tape in'cyclic accord with the electrical transmission of the same code signal. 9.'A keyboard-operated code signaling device havingimeans for permutationally punching holes in a tape and for feeding said tape across a punching position, mechanism for momentarily storing a condition representing a permutational set-upxof code elements to be punched in said tape'corresponding to a character selected by key actuation, a transmitting distributor having continuously driven brushes and segments corresponding to the code elements, contact devices for feeding a signal potentialto selected ones of said segments and thence through a first one of said brushes to a communication channel, locking means for maintaining each code set-up during a period commencing with the actuation of a selected key and including the passage of said brush over predeterminedones of said distributor segments, storage means connected to theremaining segments and actuable priorto the sweeping of said brush thereover for producing a hang-over of said code set-up beyondthe maintenance period of said locking means, and means including local circuits closeable by a second one of said brushes for performing a punching operation on said tape and for subsequently terminating the effective period'of said locking means.

10-;In combination, a keyboard-operated code composingmechanism, a tape perforator having punches selectable by said mechanism, a set of code-element contacts selectively closeable by said mechanism, a continuously operable distributor through which circuits individual to the code elements of a character signal are successively connected to a line, and periodic timing means operable in synchronism with said distributor for causing selected punches of said perforator to perforate a tape, thereby to record the selected" code element combinations simultaneously with the signal transmission thereof.

11. The combination according to claim 10 and including a plurality of blankf-signal-composing contacts and means for causing the same to be effective for-transmitting a, blank signal whenever the operationof said code composing mechanism ceases to be maintained in step with said distributor.

-12. The-combination according to claim 10 and including relays in certain of said code element circuits; said relays constituting means for introducinga hang-over of effects of'said code composing mechanism after the latter has been restored to normal.

' RICHARD E. MA'IHES.

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